Low level components are combined in clusters that perform a specific software function.

A driver (control program) is written to coordinate test case input and output.

The cluster is tested.

Drivers are removed and clusters are combined moving upward in the program structure.

15.
Bottom - Up Top - Down Big Bang Sandwich Integration Early Early Early Time to get working program Late Early Late Early Drivers Yes No Yes Yes Stub No Yes Yes Yes Parallelism Medium Low High Medium Test specification Easy Hard Easy Medium Product control seq. Easy Hard Easy Hard

Ensure that each function or performance characteristic conforms to its specification.

Deviations (deficiencies) must be negotiated with the customer to establish a means for resolving the errors.

Configuration review or audit is used to ensure that all elements of the software configuration have been properly developed, cataloged, and documented to allow its support during its maintenance phase.